Cliff Arnall is back, and he’s got enough dodgy “formula for” stories to see us through til Christmas. The man behind the worst and best days ever has now come up with a formula for the “perfect toy”. As with all the finest scientific research, you can find the details in the Daily Mail.

If you don’t remember him, Cliff Arnall often pops up in to the media peddling mathematical nonsense. The Mail bill him as “Professor” Arnall, which is a new one, but it’s not entirely clear which institution he’s from. Certainly not Cardiff University, who have made repeated attempts to distance themselves from Arnall after he left their employ as a part-time tutor.

Let’s have some fun playing with the formula then. The Daily Mail have a handy explanation:

All the variables in the left column are basically arbitrary scores out of 5, and thus fairly meaningless. In the right column, T, L and C are at least all quantifiable, in that we can assign a meaningful value to them. Multiplying T by L is actually fine, because both of these variables use units of time. The problems start when you divide by the square root of C.

Quick anyone, what’s the square root of £1? I might as well ask for banana divided by orange – neither question makes mathematical sense, because there is no such thing as the square root of currency.

Our old friends zero and infinity make an appearance as well. If a toy is free, it doesn’t matter if you give it 0 out of 5 for everything else, because as long as your child plays with it for even a second, it’s going to have infinite play value. Dividing by smaller and smaller values of C makes the last term in the equation grow rapidly, completing dwarfing the others. In other words, Cliff Arnall’s perfect toy is crap and worthless. Just like his formulas then.